Why did they repair the first Technodrome when there plenty of them?
 

In the season 3 finale, repairs on the Technodrome from season 1 were completed. They even said the repairs had been going on since it initially crashed. But why did they bother? The Kraang were shown to have plenty of working Technodromes half a season earlier, the climax of the return arc hinged on it. What was so special about that particular Technodrome?

Wasn't it because it was the only one on Earth, since all the others were stuck in Dimension X?

Why not repair it? Even with so many technodromes at their disposal, no harm can come from repairing one and wouldn't cost them much when compared to what it would've been to make them all in the first place.

Plus what CyberCubed said, but I can't remember if there was anything explicitly stopping the Kraang from bringing over their technodromes in Dimension X to Earth.

The times we do see the inside of the other technodromes they look different from the inside of the Technodrome itself.

So it's likely that the Technodrome is the main flagship, and the other technodromes are battleships ships based off the technodrome itself.

Kinda like how in Starwars the Star Destroyers and the Dreadnaughts are similar looking in appearance, but the Dreadnaught is the more equipped battle stations.

Wasn't the Technodrome that came to Earth during late-season 1 bigger?

Hard to tell. I don't think we see any other Technodromes (aside from the Fred Wolf one) in a realistic environment, so it's difficult to compare sizes. Next to apartment complexes it's easy to estimate, not so much when the background consists of floating alien islands in a purple void.